This form is super common in classics and jazz standards. You start with a section, repeat it, move on to something else, and come back to that first idea again. Most recordings of standards like Gershwin’s “I Got Rhythm” use this form, sometimes featuring additional repetition to extend the song. Two other famous examples are “All . . .
Mastering requires additional time and work, and so it will cost more and take longer until you have the completed song or album ready to release. If you are simply producing a nice song to celebrate your great aunt’s 75th birthday party, do you really need to have it mastered? Probably not. If you are putting . . .